Visible crew/equipment: When Station 51 is dispatched to The Boat explosion, just after Captain Stanley responds, "KMG365," as he walks past the camera to the engine, we can see the open top of the set at the rear corner of the apparatus bay.
Continuity mistake: When Johnny, Roy, and Chet are at the site of the traffic accident, during this scene the shadows' lengths - from long, to short, back to long, and its directions keep changing drastically. Such as when Chet stands in the middle of the road, looking in the direction of the vehicle with the siren, his long shadow is cast to his left, but the oncoming vehicle also casts a shadow to its left (even though it's heading towards Chet), then in the next shot that vehicle's shadow has moved to its opposite side.
Continuity mistake: When Brackett is in his office talking to Patsy's manager, he's paged and then told, "Treatment room 2, STAT," and he answers, "On my way," but Brackett doesn't rush to treatment room 2, he goes to room 230 which is Patsy's room, and Early even calls for a code blue in room 230.
Continuity mistake: When Brackett and Morton are with Patsy in her hospital room, there are two closeups of the Datascope 850, but there's an entirely different unit at the foot of Patsy's bed monitoring her EKG, not the Datascope 850. The same thing happens again later, when Brackett rushes in and Early tells him that Patsy was throwing more PVCs.
Visible crew/equipment: During the structure fire, when Captain Stanley uses the HT and says "Engine 17, you can pump to Engine 51," in the next shot a second cameraman carrying a handheld camera is visible between Engine 17 and Engine 9, as he's shooting footage. He's visible again three shots later, standing beside Engine 17, and once again right after they lower the ladder through the hole in the roof.
Other mistake: At the structure fire, Roy and Johnny rescue 17's Captain Harmell, as seen on his helmet after he fell through the roof, but when Truck 17 sends its snorkel to the roof, 51's Captain Stanley and Captain Watson, whose helmet also shows 17, both assist with the rescue of the other Captain of 17.
Other mistake: When Johnny and Roy are at the construction site with the injured father and son, Rampart is also on the line with two other squads - Squad 18, treating a pulmonary edema, and Squad 36, treating a bike accident. When Marco and Chet carry up the stokes basket, we hear the dispatcher saying, "Engine 21 and Squad 18, heart case...," even though Squad 18 is already tied up with the pulmonary edema.
Character mistake: When Johnny is about to tell Roy what the problem is, the dispatcher drops tones and says "Station 51, Engine 36, Truck 116, small aircraft in trouble.," but when Captain Stanley responds we hear him say, "Squad 51, 10-4...," even though he should have said, "Station 51, 10-4...," because both Engine 51 and Squad 51 were dispatched.
Other mistake: When Roy and Johnny are working on the squad's engine, while Johnny's lying on the mechanic's creeper, Roy is holding a spray can with white tape wrapped around the top of the can, so the brand name would not be visible.
Continuity mistake: At the start of the episode, after Chet takes a spoonful of hot cheddar cheese the bowl is near his plate, but when it cuts to facing the other guys that bowl is on the other side of the table near Marco, then back and forth again.
Other mistake: After Dr. Early fixes the squad's engine problem, while Roy and Johnny are driving away, Roy's watch reads 10:30, but when the dispatcher sends them to the leg injury he says that the time out is 11:52. Then at the scene of the football player's leg injury, Roy's watch reads 8:15 and Johnny's watch reads 9:30.
Other mistake: When Tommy is in the treatment room drinking chocolate milk, the container of milk has tape wrapped around it, so the brand name would not be visible. Later at the station, when Chet is polishing the table in the kitchen, the spray can he's using has tape wrapped around it as well, for the same reason.
Revealing mistake: At the start of the episode, in the closeup shot of Chet, Roy, and Johnny as they're talking about their trip, we can see the Land Rover hood's base plate where the vehicle's spare tire is supposed to be mounted, but the tire isn't there because of the mounted camera facing the actors in the vehicle. In other shots the spare tire is properly mounted on the Land Rover's hood.
Character mistake: After the cat has her kittens, when Squad 51 is dispatched to the 'man trapped in boating accident', we hear Captain Stanley respond, "Station 51, KMG365," even though his response should have been, "Squad 51, KMG365," since it's only John and Roy that were dispatched, not the entire station.
Continuity mistake: While Squad 51 is out on the run (quite literally) with the female OD, Johnny gets a cut on his elbow which he keeps fidgeting with even after it's bandaged. When Roy and Johnny get back to the station and see The Old Engine, Johnny's cut has vanished.
Other mistake: When the dispatcher sends Squad 51 to the heart attack at the bank robbery location, the address is given as "2057 North Hillcrest, cross street Barker," but when they arrive at the corner bank, the sign reads Celis Street.
Continuity mistake: When Johnny and Roy are on the "child locked in a bathroom" run, Johnny makes a hasty retreat leaving Roy to deal with the "child." The bar of soap Roy uses is on a curved pedestal soap dish, and that dish is either curved towards the wall, or turned the opposite way, depending on the camera angle.
Propinquity - S3-E20
Other mistake: When Station 51 is dispatched to the traffic accident, while en route first we see Engine 51 with nobody on the back, but then we see two firemen standing at the back, and they are Johnny and Roy. This footage is from the episode "The Old Engine" in season 3, when Station 51 got the new Ward La France engine, and since the previous shift was still out with the squad, Cap told Roy and Johnny to jump on the back and join them on their first run with the new engine.
Inventions - S3-E22
Other mistake: After Johnny and Roy are seen carrying the semi-conscious worker during the chemical leak, Captain Stanley tells Mike to get the life gun, and tells Chet to secure a lifeline, then before he mentions getting the guys from the catwalk via the lifeline, we hear Captain Stanley tell the Battalion Chief (into his handie-talkie), "Battalion 14, Engine 41," even though he's Engine 51, not 41. Additionally, when Cap tells Chet about the lifeline, two firemen behind Chet are wearing helmets with no company numbers on them.
The Promise - S3-E11
Other mistake: When Johnny and Roy get back to the station, Chet tells Johnny that Paula's going to come by around 12:30 PM, then when the dispatcher sends Squad 51 on the 'woman down' run he says "Time out 12:22." When the guys get back to the station again, Paula tells Johnny that she arrived around noon and that Engine 51 left on a run shortly after.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy